Mixer



United States ljatent C) 3,166,301 MIXER William A. Wootten, Palos Verdes Estates, Calif., assigner to Magnetic Film and Tape Company, Inc., Gardena, Calif., a corporation of California Filed Get. 22, 1962, Ser. No. 232,003 7 Claims. (Cl. 259-21) The present invention relates generally to mixing and grinding devices for particular material and, more particularly, to such devices in which the particulate material is suspended in a liquid medium.

In mixing finely divided particulate material with liquid carriers, it is desired to break up any coherent groups of particles and to distribute them as evenly and nely as possible throughout the carrier liquid. At the same time, it may be desired to further comminute the particulate material to a smaller size during the mixing operation. Devices of this type are used, by way of example only, in the mixing and grinding of finely divided particulate solid material, such as iron oxide and pigments, such as lead oxide, suspended in liquid lacquers, binders and thinners and in aqueous slurries. According to the present invention, the particulate material suspended in the liquid carrier is passed between sliding surfaces which are urged toward each other by a resilient bias. In their passage between the relatively sliding surfaces, groups and clumps of particles are broken up into their individual constituents, and the particles themselves are reduced to a smaller size. A large effective mixing and grinding area is provided in a minimum of overall space by means of a plurality of interlaced, rotatable disc members, freely spring biased together and between the contacting surfaces of which the carrier liquid and suspended particulate pass.

An object of the present invention is the provision of an improved mixer and grinder for particulate material.

Another object of this invention is the provision of an improved mixing and grinding device of relatively small size providing large relatively movable areas between which a carrier liquid and a particulate suspended there- 1n pass.

A further object of this invention is the provision of an improved mixing device for breaking up and thoroughly distributing a comminuted particulate material in a liquid carrier medium.

A still further object of this invention is the provision of an improved mixing device for particulate material suspended in a liquid carrier, having relatively sliding surfaces provided by interleaved central and outer discs urged together under a resilient bias.

These and other objects and features of the invention will be readily apparent -to those skilled in the art from the following specification and the appended drawing illustrating a presently preferred embodiment of the invention, in which:

FIG. l is a vertical sectional view through a mixing and grinding device according to the present invention;

FIG. 2 is a horizontal transverse sectional view in the plane 2-2 of FIG. l; and

FIG. 3 is a partial sectional View similar to FIG. 2 and showing a modified arrangement.

In the embodiment selected for illustration in the drawing, the mixer according to the present invention has a main body portion indicated generally at 11, and comprised of a cylindrical portion 12 having top and bottom plates 13 and 14 bolted thereto, as by studs 15. Seals 16 and 17 are provided at the junctions of the plates 13, 14 and the central cylindrical portion 12. Suspended from the bottom plate 14, as by studs 18, is a cylindrical housing 19 sealed thereto by a seal 20. The bottom of housing 19 is closed by a bottom cap 21 which retains a bearing 22 within an inner bottom socket 23 in the housing 19.

ICC

Within the bearing 22 is rotatably mounted the lower end of a shaft 24 having a central bore 25 closed by an end plug 26 welded therein and forming an extension of the shaft. Radial openings 27 communicate the shaft bore 25 with the interior of the housing 19. An inlet into the interior of the housing 19 for the carrier liquid and suspended particulate material is indicated by a pipe 28 through which the liquid and material flow under pressure from a source, not shown. A thrust bearing 29 in the bottom plate 14 holds the shaft 24 against downward movement.

A split collar 31 is provided about the shaft 24 and is anchored axially thereof by its disposal in an annular circumferential groove 32 therein. Adjacent the bottom of the housing 19 there is mounted a carbon plate 33 in an interior annular socket 34 therein. Axially slidably mounted on the shaft 24 above the carbon plate 33 is a cup-shaped member 35 having at least a Stellite bearing face engaging 4the upper surface of the carbon plate 33 in sealing, rotatable relation. Within the cup-shaped member 35 and about the shaft 34 is mounted a sealing ring 36 against which bears a sleeve 37 contacted at its upper end by a spring guide member 38. A spiral compression spring 39 is disposed between the collar 31 and the spring guide member 3S and biases the sleeve 37 against the sealing ring 36 to thereby supply a spring biased seal against the shaft 24. A pin 41 interconnects the members 35, 37 and 38 to insure their rotation together with the shaft 24, the spring 39 and collar 31 also 'rotating therewith.

Upon the top plate 13 is mounted a generally cylindrical housing 45, as by studs 46, and sealed thereto by a seal 40. A bearing 47 -is disposed in an upwardly opening annular notch 48 interiorly of the housing 45 and is held therein by a top cap 49 threaded into the housing. A carbon plate 51, similar to the plate 33, is mounted in a downwardly directed annular notch 52 in the housing 45. A cup-shaped, axially movable, Stellite bearing member 53 is provided about the shaft 24, and a sealing ring 54 is disposed therein and engaged by an axially movable sleeve 55 about the shaft 24. An annular spring guide 56 engages the bottom surface of the sleeve 55 and a coiled `compression spring 57 is disposed between the spring guide 56 and a double-ended collar 58 of split formation and located Within an annular groove 59 in the circumference of the shaft 24. The collar 58 has axially extending openings 61 therethrough for the passage of the carrier liquid and the suspended particulate material as it passes through the housing 45 to an outlet 62 therefrom. The upper surface of the member 53 forms a rotating seal against the plate 51.

Upon the shaft 24 within the cylindrical body portion 12 are mounted a plurality of discs 63, freely slidable axially of the shaft 24 but individually keyed thereto at 64 so as to rotate therewith. The discs 63 are spaced apart by a plurality of smaller, outer discs 65. The discs 65 are slidably mounted on stationary posts 66 which are threaded at their lower ends into the lower body plate 14 and have their upper ends disposed in sockets in the upper body plate 13, the posts 66 being thereby held rigidly in a ver-tical position, as viewed in FIG. l. The discs 65 are freely rotatable on the stationary posts 66 and are slidable axially thereof.

The outer discs 65 and the central discs 63 are therefore mounted in interleaved relation, as shown in FIG. 1 of the drawing, with their adjacent surfaces contacting and with the outer discs 65, six in number as shown in the drawing, between any two adjacent central discs 63 being disposed in the same horizontal plane. The smaller, outer discs 65 are dimensioned and located so that their peripheral edges contact adjacent to the periphery of the central discs 63, so that there is no direct connection between the space about the shaft 24 between the central discs 63 and the main mixer chamber within the cylindrical body portion 12.

A relatively heavy compression spring 68 is disposed between the collar 58 and the upper central disc 63 and serves -to bias all of the discs 63 and 65 together so that their contacting surfaces engage under the resilient bias exerted by the spring. Radial holes 69 extend through the walls of the central hollow portion of the shaft 24 to communicate its bore Z with the spaces between the central discs 63 mounted thereon.

A driving means for rotating the shaft 24 is indicated generally at 7l and may be, for example, an electric motor.

As the shaft 24 rotates, for example, clockwise, as shown by the arrow in FIG. 2, the discs 63 will be positively rotated therewith. The discs 65, being freely rotatable on their posts 66, will be rotated by the discs 63 due to the frictional engagement between the contacting surfaces thereof, Vand 4the discs 65 will rotate in the direction of the arrows of FIG. 2, that is, counterclockwise. Any freedom in the pivotal mounting of the discs 65 on the posts 66 is taken up by movement of the discs radially inwardly under the force exerted thereon by the frictional engagement of the discs 63 therewith. This tends to move the discs 65 into edgewise engagement at 72, to prevent passage of the liquid and suspended particulate between ythe edges of the discs 65. It will be noted that at their engagements '72 the adjacent discs 65 are rotating in op- ;posite directions, so that there is no tendency to progressively move the carrier and its particulate forwardly be- .tween the discs.

The carrier liquid and the particulate suspended therein are fed into the mixer throughl the inlet 28 under con-k siderable pressure and move through the housing 19 and ,the openings 27 into the bore 25 of the shaft 24. From .the Vbore they pass radially outwardly through the openings 69 into the spaces between the central discs 63. .The carrier liquid and the particulate therein cannot pass directly from the spaces between the central discs 63 into the free space immediately adjacent the central cylindrical body portion l2 because such direct communicaltion is sealed off by the engagement of the discs at 72, ,and passage of the carrier liquid and the particulate past the point 72 is preferably kept at a minimum. The pressure on the carrier liquid exerted on the discs 63 tends to move them upwardly against the bias of the spring 68 to effect a slight resilient separation between the surfaces of the central discs 63 and the outer discs 65 disposed therebetween. The carrier liquid and the particulate thus flow into the spaces between the adjacent faces of the central and outer discs and move outwardly between these rela- Vtively sliding faces into the main well of the mixer within the central cylindrical body portion lli.

As the discs 65 are drivengby'the central discs 63, it `willfbe'noted-that the adjacent vdisc surfaces not only `rotate together, but there is sliding relative movement between the central and outer discs as contacting points thereon have relative radial movement as well as common rotary movement. There occurs, therefore, a passage of f'rtherpariticulate lmaterial vbetween relatively sliding surfaces urged` together under a resilient bias. In its passage be- 'tween such relatively sliding pressure surfaces, the par- ,ticulate'is ecectively broken up and distributed, and further comminuted. After passing between the contacting :flat surfaces of the discs 63 and 65, the carrier liquid and the suspended particulate, now thoroughly mixed and dis- -tributed'thereim pass freely from the body portion of the mixer throughthe central opening 75 in the top plate 13 into the housing 45, whence the material llows out through the outlet 62.

rlhe pressure between the discs 63 and 65 may be :adjusted by replacement of the spring 68, or the collar 5S may be made adjustable to regula-te the compression on '-the spring. However, while increased pressure would tend to fur-ther grind the particulate material between the flat surfaces of the discs 63 and 65, if it could be made to pass therethrough, if this pressure on the discs is made too high, then the pressure on the liquid in the spaces between the discs 63 may become-so high that the discs 65 may be moved outwardly and separate at the points '72 to permit unground particulate to pass directly into the mixer well. Such outward movement of the discs 65 might be permitted by the slop or bearing wear normally occurl-ing therein. Y v 1 To further prevent this outward movement of the discs 65, and thus permit a greater axial pressure upon the discs, the embodiment of FIG. 3 is used to apply a direct spring bias to the discs 65, tending to move them radially inwardly of the shaft 24 andk assisting the inward movement of the discs 65 previously explained as occurring upon driving thereof by the discs 63. ln the arrangement of FIG. 3, the cylindrical body portion t2 is replaced by a similar cylindrical body portion 76 having six integral bosses 77 thereon, one opposite each of the posts 66 Vupon which the discs 65 are mounted. Elongated rollers i8 are mounted on carriers ii-disposed within axially and radially extending recesses Sl in the bosses '77. Springs 32 in the recesses el bias the carriers .73 and the rollers .78 radially inwardly toward the shaft 24, and the rollers 73 are thereby resiiiently held against the edges of the disc 65. Thereby the pressure exerted on the discs 65 by the liquid within the `Spaces between the discs and tending to move the discs outwardly is opposed not only by the inherent tendency of the discs 65 to move inwardly under the driving action of the discs 63, but also by the resilient bias provided by the springs 82 acting on the rollers iS engaging the edges of the discs 65. With the arrangement of FIG. 3, the tendency of the particulate to flow between the edges of the discs 65 without Vpassing between the horizontal fiat surfaces of the discs 63 and 65 is lessened, and greater pressures between the disc surfaces and in the carrier liquid can be accomy modated.

While certain preferred embodiments of the invention have been specifically illustrated and described, it will be understood that the invention is not limited thereto, as many variations will be apparent to those skilled in the art, and the invention isfto be given its broadest interpretation within the terms of the following claims.

l claim:

1. A mixing device comprising: a central shaft; a plurality of discs mounted on said shaft to be rotatable therewith but slidable axially thereof; a plurality of outer discs mounted for rotation about axes disposed adjacent to the peripheries of said central shaft discs, said outer discs being interleaved with said central discs so that said central discs are separated from each other by said outer discs, said outer discs being freely rotatable and axially movable; -means axially biasing said central and outer discs together; means for rotating `said shaft; and means .for passing particulate material past the adjacent surfaces of said central and outer discs, the edges of said outer discs engaging not substantially outwardly of the peripheries of said central discs so as to prevent direct communication between the spaces between said central discs and the spaces outwardly of the peripheries thereof.

2. A mixing device comprising: a central hollow shaft; a plurality of discs mounted on said shaft to be rotatable therewith but slidable axially thereof; a plurality of outer .discs mounted for rotation about axes disposed adjacent to the peripheries of said central shaft discs, said outer Adiscs being Vinterleaved with said central discs so that said central discs are separated from each other by said outer discs, said outer discs being freely rotatable and axially movable; means axially biasing said central and outer discs together; means for rotating said shaft; means for passing particulate material through said hollow shaft and past the adjacent surfaces on said central and outer discs, the edges of said outer discs engaging not substantially outwardly of the peripheries of said central discs so as to prevent direct communication between the spaces between said central discs and the spaces outwardly of the peripheries thereof; and means for feeding particulate material through said hollow shaft into the spaces between said central discs and thence between the adjacent surfaces of the central and outer discs into spaces outwardly of the peripheries of said central discs. p

3. A mixing device comprising: a central hollow shaft; a plurality of discs mounted on said shaft to be rotatable therewith but slidable axially thereof; a plurality of outer discs mounted for rotation about axes disposed adjacent to the peripheries of said central shaft discs, said -outer discs being interleaved with said central discs so that said central discs are separated from each other by said outer discs, said outer discs being freely rotatable and axially movable; means axially biasing said central and outer discs together; means for passing particulate material through said hollow shaft and past the adjacent surfaces on said central and outer discs, the edges of said outer discs engaging not substantially outwardly of the peripheries of said central discs so as to prevent direct cornmunication between the spaces between said central discs and the spaces outwardly of the peripheries thereof; and means for positively driving said shaft and said central discs so that said outer discs rotate therewith by the frictional engagement between their surfaces and movement of the particulate between the adjacentl surfaces of the central and outer discs is accompanied by substantial relative sliding movement between the surfaces of the central and outer discs radially thereof to increase the mixing and grinding action on the particulate passing therebe tween. Y

4. A mixing device comprising: a central hollow shaft; a plurality of discs mounted on said shaft to be rotatable therewith but slidable axially thereof; a plurality of outer discs mounted for rotation about axes disposed adjacent to the peripheries of said central shaft discs, said outer discs being interleaved with said central discs so that said central discs are separated from each other by said outer discs, said outer discs being freely rotatable and axially movable; means axially biasing `said central and outer discs together; means for rotating said shaft; means passing particulate material through hollow shaft and past the adjacent surfaces on said central and outer discs, the edges of said outer discs engaging not substantially outwardly of the peripheries of said central discs so as to prevent direct communication between the spaces between said central discs and the spaces outwardly of the peripheries thereof; and means for resiliently biasing said outer discs toward the axis of rotation of said shaft so as to maintain the edges of adjacent outer discs in engagement and inhibit direct flow of particulate therepast.

5. A mixing device comprising: a housing providing a container; a hollow shaft extending across said container and rotatable relative thereto; a plurality of supporting posts mounted in said container in a ring concentric with the axis of rotation of said shaft; a plurality of central discs mounted on said shaft for rotation therewith and for movement axially thereof; a plurality of outer discs mounted on said posts for free rotational and axial movement relative thereto, said post-mounted discs being interleaved with said central discs by being mounted in common planes between each adjacent pair of central discs; means axially biasing said central and outer discs together; means for rotating said shaft to positively drive the central discs and to drive the outer discs by frictional engagement therewith; and mean-s to feed particulate material through said hollow shaft into the spaces between Said Central discs, whence it moves between the engaging surfaces of the central and outer discs into the container outside of the'peripheries of `said central discs.

6. A mixing device comprising: a housing providing a container; a hollow shaft extending across said container and rotatable relative thereto; a plurality of supporting posts mounted in said container in a ring concentric with the axis of rotation ofV said shaft; a plurality of central discs mounted on said shaft for rotation therewith and for movement axially thereof; a plurality of outer discs mounted on said posts for free rotational and axial movement relative thereto, said post-mounted discs being interleaved with said central discs by being mounted in common planes between each adjacent pair of central discs; and means axially biasing said central and outer discs together; means for rotating said shaft to positively drive the central discs and to drive the outer discs by frictional engagement therewith; and means to feed particulate material through said hollow shaft into the spaces between said central discs, whence it movesV between the engaging surfaces of the central and outer discs into the container outside of the peripheries of said central discs, said supporting posts being spaced apart a distance substantially equalto the diameter of said outer discs so that the edges of said outer discs are substantially in engagement to prevent direct passage of the particulate from the spaces between the central discs into the container beyond the central discs.

7. A mixing device comprising: a housing providing a container; a hollow shaft extending across said container and rotatable relative thereto; a plurality of supporting posts mounted in said container in a ring concentric with the axisrof rotation of said shaft; a plurality of central discs mounted on said shaft for rotation therewith and for' movement axially thereof; a plurality of outer discs mounted on said posts for free rotational and axial movement relative thereto, said post-mounted discs being inter-` leaved with said central discs by being mounted in common planes between each adjacent pair of central discs; means axially biasing said central and outer discs together; means for rotating said shaft to positively drive the central discs and to drive the outer discs by frictional engagement therewith; means to feed particulate material through said hollow shaft into the spaces between said central discs, whence it moves between the engaging surfaces of the central and outer discs into the container outside of the periphery of said central discs, said supporting posts being spaced apart a distance substantially equal to the diameter of said outer discs so that the edges of said outer discs are substantially in engagement to prevent direct passage of the particulate from the space between the central discs into the container beyond the central discs; and means biasing the outer discs inwardly toward the central shaft to encourage contact between the adjacent edges of the outer discs.

References Cited in the file of this patent UNITED STATES PATENTS 2,170,303 Helstrup Aug. 22, 1939 2,176,892 Dotzer et al Oct. 24, 1939 2,509,379 Vasel May 30, 1950 2,581,451 Sennet Ian. 8, 1952 2,631,016 Laubarede Mar. l0, 1953 2,668,756 Carney Feb. 9, 1954 2,731,083 Broden et al Jan. 17, 1956 2,903,192 Clausen Sept. 8, 1959 3,055,249 Lord Sept. 25, 1962 FOREIGN PATENTS 54,427 Germany -V-Y-fw-:f-ff- Novi 1.5; 1,890 

1. A MIXING DEVICE COMPRISING: A CENTRAL SHAFT; A PLURALITY OF DISCS MOUNTED ON SAID SHAFT TO BE ROTATABLE THEREWITH BUT SLIDABLE AXIALLY THEREOF; A PLURALITY OF OUTER DISCS MOUNTED FOR ROTATION ABOUT AXES DISPOSED ADJACENT TO THE PERIPHERIES OF SAID CENTRAL SHAFT DISCS, AND OUTER DISCS BEING INTERLEAVED WITH SAID DISCS SO THAT SAID CENTRAL DISCS ARE SEPARATED FROM EACH OHTER BY SAID OUTER DISCS, SAID DISCS BEING FREELY ROTATABLE AND AXIALLY MOVABLE; MEANS AXIALLY BIASING SAID CENTRAL AND OUTER DISCS TOGETHER; MEANS FOR ROTATING SAID SHAFT; AND MEANS 